I call "group" a section of the army that is meant to work together. Like, a LR carrying termies, plus a Rhino w/Tacticals trailing behind it, and an Arquitor giving it fire support, that'd be a Group.
What do you call that? What are your groups made of?

I call "speahead" to the forward part of the group. It's the part that ideally makes contact first. In that example it is the Terminators punching a hole in the enemy's line that my own Line can exploit. What do you use as a Speartip?